AC Milan will be without defender Thiago Silva for Sunday's derby against Inter Milan, a crucial game which could yet prove to be the scudetto decider.
The Brazilian trained separately from the rest of the first team squad on Friday and has been struggling with a muscle injury.
Inter's Dejan Stankovic will miss the Milan derby after an ongoing Achilles problem finally put paid to his season.
Leaders Juventus travel to Trieste, where they play Cagliari on Sunday, without Paolo De Ceglie. The defender will miss the season's two remaining league games, and possibly the Coppa Italia final against Napoli, after suffering a thigh injury.
"I said yes for the love of Fiorentina," Guerini told a news conference on Friday.
Earlier, former coach Delio Rossi, sacked after punching player Adem Ljajic during Wednesday's game with Novara, was embraced by fans gathered outside the club's Stadio Franchi after apologising for the incident.
For his part, Ljajic has said sorry to Rossi via his Facebook page, adding that he "wishes Signor Rossi the best for the future". Earn a point at Lecce on Saturday and Fiorentina will be safe.
Speaking at a specially-arranged news conference on Friday, the former Italy international did not rule out a future return to the club, possibly in a coaching or director's role.
Napoli president Aurelio De Laurentiis says the club "are masters of our own destiny" as they look to secure third place and another crack at the Champions League.
Thousands of travelling fans will accompany the team for Sunday's game at Bologna, where striker Ezequiel Lavezzi is expected to again start on the bench.
"I sent him an SMS," De Laurentiis told Italian radio. "He's a true Neapolitan, even if he doesn't actually realise it."
